Queen Elizabeth II, head of state of the United Kingdom and of 31 other states and territories, is the legal owner of about 6,600 million acres of land, one sixth of the earth’s non ocean surface.

She is the only person on earth who owns whole countries, and who owns countries that are not her own domestic territory. This land ownership is separate from her role as head of state and is different from other monarchies where no such claim is made – Norway, Belgium, Denmark etc.

Actually, the article about the Queen 'owning' so much is pretty simplistic...Imagine if she, personally tried to exercise these alleged rights of ownership over any parts of Oz, NZ or Canada...they would give the two fingered salute and replace her as the "Head of State" within weeks.
Even in the UK I think the 'rights' are largely theoretical.

Here in Hayle in Cornwall, the Rail companies own the railway and station, and choose not to have the trains stop. They own lines and bridges that they will not service or renovate.

The RSPB own the estuaries and tidal pools, and together with the Environment Agency decide when the tidal waters will be allowed in or out.

I.N.G. real estate own the harbours and surrounding land.

English Nature, RSPB, SWRDA, World Heritage, and other bodies based outside the Duchy have a great say in what can and can't happen.

Most of us who 'own' our homes pay cash and homage to Building Societies, and pretty well any major development, scheme or 'regeneration' depends on grant aid or other funding from outside the area.